Failure Code [Ca689] Engine Ne Speed Sensor Error - Komatsu WA250-6 Shop Manual

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Failure code [CA689] Engine Ne speed sensor error

Failure code

• Abnormality occurred in signals from engine Ne speed sensor.

• Controls Ne speed sensor with signals of Bkup speed sensor.

• Turns the centralized warning lamp and alarm buzzer ON.

• There is hunting from engine.

Problem that

• Starting performance is poor

• Engine output drops.

• Method of reproducing failure code: Start engine

Defective Ne speed sensor

power supply system

Defective engine Ne speed

Broken engine Ne speed

sensor or defective clear-

Broken rotation sensing fly-

Disconnection in wiring har-

Possible causes

and standard

(Disconnection or defective

value in normal

contact in connector)

Ground fault in wiring har-

(Contact with ground circuit)

Hot short (Contact with 5V,

24V circuit) in wiring harness

Short circuit in wiring har-

(with another wiring harness)

330 Troubleshooting by failure code (Display of code), Part 3

Failure code [CA689] Engine Ne speed sensor error

Engine Ne speed sensor error

(Engine controller system)

Standard value in normal state/Remarks on troubleshooting

If failure code [CA238] is indicated simultaneously, carry out trouble-

shooting for it first.

a Prepare with starting switch OFF, then turn starting switch ON

and carry out troubleshooting.

CRANK SENSOR

Between (1) and (2)

Voltage is measured with wiring harness connected. Accordingly, if

voltage is abnormal, check wiring harness and controller, too, for

another cause of trouble, and then judge.

Inspect engine Ne speed sensor for breakage or clearance.

Inspect it for breakage directly.

a Prepare with starting switch OFF, then carry out troubleshooting

without turning starting switch ON.